The present invention relates to medical and surgical wound dressings and methods for making and using such dressings. In particular, the present invention relates to medical and surgical wound dressings where the wound dressing incorporates a water-soluble molding matrix to cause the resulting wound dressing to slough as particles of predictable maximum size and geometry. The medical and surgical wound dressings of the present invention provide a treatment to seal post-surgical sites of the oral and pharyngeal space that do not pose a choking hazard.
Approximately one million tonsillectomies, adenoidectomies, and tonsillectomy/adenoidectomy procedures combined were coded as surgical procedures in the United States in 2007. Although tonsillectomies and adenoidectomies are considered to be safe procedures, they still have significant morbidities of pain and postoperative bleeding. Post-operative pain causes great discomfort upon swallowing. In an attempt to avoid this pain, patients may experience dehydration and poor oral intake due to their lack of drinking and eating. The ideal treatment would alleviate pain without introducing additional safety risks such as choking.
After tonsillectomy, the risk of clinically significant aspiration of the “scab” appears to be near zero. It is not known whether the scab sloughs mostly intact or mostly in fragments. If it sloughs in fragments, fragment sizes are unknown. Route of elimination of the scab is unknown: coughing or swallowing? This lack of knowledge regarding the natural history of the tonsillectomy scab presents a challenge to the design of a protective wound dressing. It is desirable to create a dressing that reduces pain and reduces postoperative bleeding, but the dressing cannot cause complications such as choking, aspiration, or ingestion when the dressing is sloughed from the wound bed during healing.
Foreign body ingestion and aspiration are primarily pediatric problems. Since 1979 the United States has had regulations in effect which ban interstate commerce of any toy or other article intended for use by children under the age of three that presents a small parts choking hazard. There is a test fixture called a Small Parts Test Fixture used to determine if an object may cause a choking hazard for small children. The cylinder has a diameter of 31.7 mm and a depth of 25.4 to 57.2 mm (the cylinder has an angled top). The test method is described in 16 CFR Part 150: Method for Identifying Toys and Other Articles Intended for Use by Children Under 3 Years of Age Which Present Choking, Aspiration, or Ingestion Hazards Because of Small Parts. In a 1995 study of 534 incidents, 99% of aspirated foreign bodies would fail this test (Reilly J S et al, Size/shape analysis of aerodigestive foreign bodies in children: a multi-institutional study. American Journal of Otolaryngology. 1995; 16:190-193.). Nonetheless, the Small Parts Test Fixture is utilized in much of the world including Europe, the Americas, and China to prevent choking in children. In Reilly's study airway foreign bodies had an average length of 13.6 mm, width of 7.0 mm, and height of 5.7 mm. To not pose a choking hazard, it appears a fragment smaller than these dimensions is desirable.
A number of techniques have been evaluated for their ability to reduce the post-operative pain for these procedures. The Coblation Tonsillectomy procedure developed by ArthroCare Corporation (Austin, Tex.) was developed as a “less invasive” and thus less painful tonsillectomy method. This system utilizes radiofrequency to simultaneously ablate, resect, coagulate soft tissue, and provide hemostasis of blood vessels in a single device. Radiofrequency generates relatively low temperatures and reduces the amount of tissue damage. However, even with use of this surgical method, post-operative pain and bleeding are still significant morbidities.
Coverage of the post-surgical area has also been evaluated as a potential treatment for post-operative pain and bleeding. Grafting the peritonsillar fossa with an acellular dermal graft in a small study showed promise in pain reduction. However, the cost of this treatment is not commensurate with the reimbursement level for these surgical procedures. (Sclafani A P, Jacono A A, Dolitsky. Grafting of the peritonsillar fossa with an acellular dermal graft to reduce posttonsillectomy pain. Am J. Otolaryngol. 2001; 22:409-414.) In another study, the faucial pillar of the tonsil was sutured. This study showed no reduction in pain and, in fact, a greater complication rate. (Ramjettan S, Singh B. Are sutured faucial pillars really an advantage in tonsillectomy? SATS 1996; 34:189-191.)
Various biological and synthetic products have been evaluated as potential tonsillectomy dressings. These appear to suffer from a limited ability to adhere to the operative site (adherence), ability to hold together (cohesiveness), and/or ability to remain in place for a clinically relevant period (durability). As an example, fibrin sealants have been applied to the tonsillar fossa to help control post-operative bleeding and pain. Results reported in the literature regarding the effectiveness of this treatment have been mixed. Fibrin sealants lack the durability to protect the wound through the time of healing. The sealant sloughs off the site before full healing is achieved. Currently neither fibrin sealants nor any other product is approved or labeled by the Food and Drug Administration to control post-operative bleeding or pain in these specific procedures.
U.S. patent application Ser. No. 11/704,115, filed Feb. 8, 2007 by Hissong et al discloses use of a polymeric film-forming medical sealant for application to the tonsils and adenoids. The sealant performs at least one of the following functions a) inhibit the colonization of bacteria, b) inhibit the binding of bacteria to tissue, c) reduction of tissue morbidity, d) hemostasis, e) coating and protection of tissue during healing, and f) reduction of pain. Hissong et al discloses preferred polymeric film-forming medical sealants, but does not disclose how the polymeric film-forming medical sealant would slough from the tonsillectomy fossa.
U.S. Pat. No. 6,559,350 to Teterault et. al. discloses a moisture-curable adhesive suture strip for closing a wound on a patient. The suture strip is comprised of an air-permeable backing member formed of a chemically inert material, a moisture-curable surgical adhesive, and a removable protective member releasably secured to the backing member and covering the surgical adhesive. The backing member is formed of chemically inert materials such as polyethylene or tetrafluoroethylene. The backing member is described as having surface cavities filled with the surgical adhesive to anchor the backing member to the patient. Alternatively, the surgical adhesive may be applied as dots or stripes to the backing member. Based on the materials disclosed for the backing member, fragmentation is unlikely. The suture strip may slough more like a balloon and cause a greater choking hazard due to its conforming nature.
U.S. patent application Ser. No. 11/124,831, Filed May 9, 2005 by Kotzev et al discloses bioresorbable cyanoacrylate-based adhesives containing body fluid soluble additives. The body soluble additives are insoluble in cyanoacrylate monomer, but are readily dissolved out of the cured adhesive creating pores and channels for tissue ingrowth. The body soluble additives are used to facilitate resorption of the bulk material at a controllable resorption rate upon contact with a body fluid. As the body soluble additive are dispersed throughout the cyanoacrylate monomer, pores and channels are created as body fluids erode the bulk material. These pores and channels create random defects in the bulk material. When fragments are created their size is unpredictable.
Therefore, a need exists for a protective wound dressing that would help patients recover from tonsillectomy and adenoidectomy procedures. The post-operative treatment should fulfill several needs of the patient. This treatment must be both safe and effective. The treatment could be accomplished through the use of a protective wound dressing. Ideally, the wound dressing would act as a barrier and would protect tissue at and around the surgical site to make it easier and less painful for a patient to swallow. The wound dressing would adhere to post-surgical tissue and mucosal tissue even with the forces of swallowing and, in addition to reducing pain, would also reduce bleeding. Most importantly, the wound dressing sloughs from the tonsillar bed in predictable pieces during healing. By sloughing in this manner, the wound dressing does not pose a choking hazard.